Depositional System Researching And Perspective Forecasting About DongYing Formation In HaiWaiHe And YueDong Structural Belt

The classic sequence stratigraphy and high resolution sequence stratigraphy theory are used by this article, to do some research about the sequence stratigraphy and depositional system in the DongYing formation of HaiWaiHe and YueDong structural belt in the middle part of TanHai area in LiaoHe fault subsidence. After the research, make some discovery that the plain distribution and vertical evolve regular pattern of the sand, the controlling factor of the oil, and forecast four profitable oil reservoir strata in the end.I recognize five tertiary sequence base in the DongYing formation, which is on the basis of cores,drilling,log and seismic data, and it is divided to four tertiary sequence, they are D3 down,D3 up,D2,D1 sequence from down to up. What I have done makes it that the tertiary seismic and well drilling sequence are well linked up in the area,and find the distribution of the sequence of the secondary building unit.I find so many sedimentary facies by the research about the depositional system in the sequence framework in the area,they are subsea apron,fan delta,braided delta,delta,dam,fluvial and lake facies. Different from the former research, I develop the new idea that it developes dam and fan delta in the middle bulge, and find the distribution of the facies in the each time. In the D3 down period, it developes braided delta at the west gentle slope, and developes subsea apron and fan delta at the east steep gradient in the west sunken; In the D3 up period, it developes fan delta in the amphi of the middle bulge at the early time, and evolves to be dam at the late time; In the D2 period, it developes dam in the middle bulge earlier, and evolves to be northern delta later; In the D1 period, it evolves to be fluvial facies , the meandering river earlier and the braid river later in the north.At the base of searching the subtle trap, I have made some research about the controlling factors of the distribution of the oil, which is that sequence framework control the layer, palaeogeomorphology control the sand, sedimentary facies control the trap, dredge system control the oil. Considering the factors about the location of the sequence stratigraphy, structure,thedistribution of sedimentary facies, the thickness of the sand, the known oil area, the style of then trap, the association of the hydrocarbon, reservoir and rock, the dredge system, I propose three vertical beneficial formations and four areal oil perspectives. They are D3 up, D3 down and D2 up hemicycle; the GaiZhouTan fracture belt, the eastern overlapping belt, the middle bulge belt, and the HaiNan fracture belt.